BF5 Sunshine Sensor

Testimonials

Measures global and diffuse radiation

Sunshine duration

No moving parts, no shade rings

PAR reference sensor for SunScan System

Outputs can be PAR (mmol.m-2.s-1), Energy (W.m-2) or Lux

The BF5 Sunshine Sensor is a versatile, multi-purpose solar radiation sensor. It uses an array of photodiodes with a unique computer-generated shading pattern to measure incident solar radiation. A microprocessor calculates the global and diffuse components of the radiation and determines the sunshine state. The BF5 Sunshine Sensor is protected by patents EP 1012633 and US 6417500.

Two analogue voltage outputs give global and diffuse radiation, from which direct and diffuse radiation are derived. The sunshine state is indicated by a digital output. The three outputs can be connected to appropriate channels on the GP1, GP2 or DL2e data loggers, or other loggers commonly used for environmental monitoring. An internal heater keeps the BF5 Sunshine Sensor clear of dew, ice and snow down to -20 degrees C.

Sunshine Duration

The BF5 Sunshine Sensor measures sunshine hours indirectly using a simple equation based on the total PAR radiation (Photosynthetically Active Radiation), and the ratio of total to direct PAR. This sunshine algorithm corresponds closely to the World Met Office threshold of 120 W/m-2 in the solar beam for sunshine duration. The BF5 Sunshine Sensor does not need to be adjusted or repositioned to track the sun – a distinct advantage over devices with shadow rings. There are no complex electro-mechanical assemblies and no burnt paper tracks to interpret.

SunScan Canopy Analysis System

The BF5 Sunshine Sensor can be used as an integral component of the SunScan Canopy Analysis system. The SunScan Probe is a 1 metre long light sensor array suitable for measuring PAR interception by plant canopies and estimating LAI (Leaf Area Index). The BF5 Sunshine Sensor improves the accuracy of the SunScan system and enables it to be used even under variable light conditions.

Applications

In addition to its role in the SunScan System, the BF5 Sunshine Sensor’s alternative outputs enable it to be used in the study of photosynthesis, illumination and solar energy measurement.

For building energy management systems (BEMS), the BF5 can be used to control the opening and closing of blinds or louvres in response to sunlight. The BF5’s ability to measure both the energy in the direct beam and also total radiation, makes it possible to optimise the use of natural light and solar gain while minimising glare for the building’s occupants.

Comparison with SPN1 Sunshine Pyranometer

The SPN1 Sunshine Pyranometer is a precision version of the BF5 Sunshine Sensor and although the two instruments have some features in common, there are important differences. These are summarised in the document: “SPN1 and BF5 Comparison Data Sheet”.

Software

Manuals

FAQs

Why are my solar radiation readings higher than the solar constant

Question

Why are my solar radiation readings higher than the solar constant

Answer

Sometimes, during the day, the sensor may read higher than the solar constant (greater than ~1370W.m-2) This is something that has been seen in rare, isolated conditions. This can usually be caused by:

Certain types of cloud cover magnifying the sun’s rays and increasing the irradiance. This tends to be when cloud cover is sporadic and the sunshine is intermittently broken up as the clouds pass by.

Water on the dome/sensing diffuser, again magnifying the irradiance seen by the sensor.

A nearby reflective object shining onto the sensor (this should be noticed at a similar time of day, every day during the same season).

These events are extreme and of short duration. They also tend to get lost if you only keep averages of the series (e.g. 1 minute samples logged every hour).

How do you insert large diameter cables (e.g. SPN1/BF5 cables) into the GP1/GP2/DL6 cable glands?

Question

How do you insert large diameter cables (e.g. SPN1/BF5 cables) into the GP1/GP2/DL6 cable glands?

Question

How do I wire my BF5/SPN1 up to a DL2e logger?

Answer

IntroductionThis document complements the SPN1 and BF5 Quick Start Guides and User Manuals. It gives a specific example of how to connect the SPN1 or BF5 to a DL2e logger. When used with a DL2e logging program the data provides hourly averages of Total and Diffuse radiation and the fraction of sun hours each hour.

SPN1 Wiring Schematic for DL2e

DL2e Logger with LAC1

This diagram shows the wiring connections for the LAC1 analogue input card. For use with other cards, please refer to the DL2e Logger User Manual.

SettingsThe example shows the SPN1/BF5 sensor outputs connected to analogue channels 1, 2 and 3 in the DL2e logger. Channel 1 DIP switches near the terminal connector must be set to the OFF (down) position. The SPN1/BF5 is a powered sensor. All analogue outputs should be read using differential channels, for best noise avoidance. The LAC1 input card of the DL2e logger is used in its 15-channel (differential) mode, with the 15-30 slider set to “15”. Power warm-up for the sensor is shown routed through relay channel 63. Power from the logger’s own battery is connected to terminal 63 using the internal jumper in the DL2e logger. The cable screen is connected to channel 61- or 62- terminals for electrical screening purposes. These are the digital earth/frame connections of the DL2e, and are also used for the Power 0V return.

Special Considerations

Relay Warm-up for Powered ChannelsThe sensor needs a warm-up signal in order to enable the circuitry to produce the output signals. Specify one of the DL2e relay channels 63 or 64, and configure it for the warm-up function with a warm-up time of 1 second.

Sun State Output OptionsThe Sun state output is shown connected to analogue channel 3. This uses an analogue channel to produce sun hours data. Analogue channel 3 is configured as a resistance channel (in the 3-wire mode). The precision 10kW resistor (0.1% tolerance) is a load resistor. If you cannot obtain this component locally, please request one from Delta-T tech support. When the sun is present, the switch contact is closed. The load resistor is thus shorted to ground and the channel will read zero ohms. With no sun, the switch contact open circuit, and the resistance reading is 10 kW. By means of special DL2e sensor codes these values can be recorded as sun hours in the logger data.

SPN1 Sensor Codes and Program for the DL2e

DL2e sensor codes for the SPN1 are included in the Ls2Win SR5 (or later) release. Please upgrade your PC installation first if it is an earlier service release version.

SPWUse this code for the Total energy (W.m-2) and Diffuse energy (W.m-2) outputs from the SPN1.

SPDSelect this code for the sun state output connected to an analogue channel, using the precision 10kW load resistor (as in the diagram above). This will give readings in sun hours per day.

Warning! You must use this code only with a 24h average period.

You must start your logging run at the time at which you want your daily total logged (e.g. midnight, or 9 am).

SPHSimilar to SPD, but this will give readings in sun hours per hour. Warning! You must use this code only with a 1h average period.A sample DL2e logger program file (e.g. SPN1xmpl.pg2) which uses the SPW and SPH code is available from Delta-T.

BF5 Sensor Codes and Program for the DL2e

DL2e sensor codes for the BF5 are included in the Ls2Win SR7 (or later) release. Please upgrade your PC installation first if it is an earlier service release version.

BFPUse this code for the Total PAR (mmol.m-2.s-1) and Diffuse PAR(mmol.m-2.s-1) outputs from the BF5. Note that it has a conversion factor of 0.8 to allow for the use of the resistor attenuator.

BFWUse this code for the Total Energy (W.m-2) and Diffuse Energy (W.m-2) outputs from the BF5. Note that it has a conversion factor of 0.8 to allow for the use of the resistor attenuator.

BFLUse this code for the Total Illuminance (klux) and Diffuse Illuminance (klux) outputs from the BF5. Note that it has a conversion factor of 0.8 to allow for the use of the resistor attenuator.

BFDSelect this code for the sun state output with an analog channel, using the precision 10kW load resistor (as in the diagram above). This will give readings in sun hours per day.Warning! You must use this code only with a 24h average period.You must start your logging run at the time at which you want your daily total logged (eg midnight, or 9 am).Warning! If you occasionally get “noisy” readings reported by the DL2e, change the sensor code Autorange function (A) to Fixed Range (F) in the logger configuration.

BFHSimilar to BFD, but this will give readings in sun hours per hour. Warning! You must use this code only with a 1h average period.

Connecting the Heater

Connect the heater wires to a suitable power supply. In air temperatures below 5°Cthe heater can consume 1.5A at 12V DC. For extended data logging in cold climates, we recommended that you power the heater via a 12 V supplypowered from the mains. Protect the heater power supply from moisture.Take particular care to check that all ground and 0V connections to the various devices attached to the sensor at any time do not create earth-loops. Refer to the sensor user manual for further guidance on this issue.

How do I set up my USB to RS232 convertor?

Question

How do I set up my USB to RS232 convertor?

Answer

These convertors usually come with a driver CD. Please make sure you load the drivers on to your PC, from the CD provided, or from the website specified in the convertor instructions. Then follow all the on screen instructions correctly.

Once the drivers have been installed correctly, plug the USB convertor into a USB port on your PC.

The computer will then assign the convertor a COM port. You will need to check which com port has been assigned via the computer’s “device manager”:

XP

Click on Start, Control Panel, System:

Under the ‘Hardware’ tab, click on ‘Device Manager’:

Windows 7

Click on Start, Control Panel, Device Manager:

Windows 8Right click on Desktop background and select ‘All Apps’

Right click on control panel and select ‘properties’:

Click on Device Manager:

Windows 10Use the search tool in the bottom task bar to search for ‘device manager’:

Once in the device manager, expand the “ports” option. The example below shows a P.C which has the USB to serial converter installed (COM3):

Please make sure that you use this same COM port number in the device software e.g. HH2read, SunRead, LS2win, DeltaLINK, AP4 retrieve.

You will probably have to re-boot the P.C once the drivers have been installed.

Also, please remember to use the original RS232 cable, that was supplied with your device, in series with the RS232 to USB converter.

Multiple USB convertor Installations check

If you have more than one USB to RS232 convertor installed, you can check which COM port has been assigned to the one you want to use, by doing the following:

Unplug the USB convertor

Open Device Manager > Ports (COM & LPT)

Plug in the USB connector and observe which COM port is added to the list